Discharge solidifier and malodour control

ABSTRACT

An ostomy bag insert ( 104 ) comprising a polyacrylate superabsorbent ( 300 ) and a powdered zeolite ( 301 ). The ostomy bag insert is configured to absorb fluids excreted by the body and to control odours resultant from the excreted matter within the ostomy bag ( 100 ). The present zeolite exhibits enhanced odour control.

The present invention relates to a superabsorbent and malodour control composition and in particular, although not exclusively, to a superabsorbent for solidifying collected matter excreted by the body and a control agent for controlling odours associated with the excreted matter.

Ostomy patients typically wear an ostomy bag into which body waste is excreted. Ostomy patients fall into three categories, each category necessitating the patient wearing an ostomy bag. Firstly, urostomy patients typically have had their bladders removed. Accordingly in this case, urine is passed through the stoma and into the ostomy bag. Secondly, colostomy patients have undergone surgery to remove all or part of the colon necessitating an ostomy bag to collect both liquid and solid excreted matter. Thirdly, ileostomy patients similarly rely upon an ostomy bag to collect excreted matter which is redirected through the abdominal wall.

Generally an ostomy bag comprises an opening which is sealed against the patient's skin around the surgically created body orifice, termed a stoma. Many ostomy bags are provided with a discharge outlet to allow excreted matter to be emptied from the ostomy bag by the patient.

When body waste is excreted into the ostomy bag it continues to release malodours which are unpleasant and can cause embarrassment to the patient. Also, where the excreted matter is in liquid form, leakage from the ostomy bag is a potential risk which would also cause embarrassment to the patient.

A number of additives have been proposed for ostomy bags designed to solidify excreted fluid matter and reduce unpleasant malodours. US 2002/0055594 discloses a superabsorbent tablet configured to thicken body excretions. The tablet comprises a superabsorbent polymer in the form of cross linked sodium or calcium polyacrylate designed to provide quick gelling of the ostomy bag contents following excretion.

U.S. Pat. No. 6,852,100 also discloses an ostomy pouch configured to reduce unpleasant odours. Superabsorbent fibres are used in combination with a malodour counteractant selected from various different categories of odour controlling (masking and neutralising) agents including for example hydrogen peroxide and bacterial growth inhibiters such as sodium nitrate and benzyl alkonium chloride.

GB 2329339 discloses a superabsorbent for an ostomy bag comprising granules of a superabsorbent formed into a stick or rod and housed within a water soluble outer sleeve. Odour counteractants, disinfectants and preservatives are also incorporated within the ostomy bag insert.

U.S. Pat. No. 5,860,959 discloses a hydroscopic composition to reduce malodours from an ostomy bag. Water absorbing materials such as starch or alkaline metal polyacrylates are employed as superabsorbents in combination with odour counteractants such as volcanic clays and activated carbon granules.

However, there exists a need for an ostomy bag insert configured to effectively solidify or gel excreted matter and control unwanted malodours.

The inventors provide a superabsorbent material for positioning within a stoma bag exhibiting superabsorbent and odour controlling properties. The superabsorbent blend has been found to exhibit enhanced malodour reduction over existing ostomy bag inserts.

According to a first aspect of the present invention there is provided an ostomy bag insert comprising: a polyacrylate superabsorbent; and a powdered zeolite; wherein the superabsorbent is coated with the powdered zeolite.

Reference within the specification to zeolite includes zeolites being microporous and capable of accommodating within their structure molecular species including ions and in particular odorous compounds typically found in fecal waste.

Optionally, the zeolite may comprise a naturally sourced zeolite mineral including in particular analcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, and stilbite.

Optionally, the zeolite is a zeolite blend comprising a hydrophilic and a hydrophobic zeolite. Alternatively, the zeolite may be substantially hydrophilic or substantially hydrophobic. A preferred hydrophobic zeolite comprises an ammonium zeolite being a zeolite having ammonium groups forming part of the zeolite structure. A preferred hydrophilic zeolite comprises a sodium aluminosilicate.

Optionally, the insert may further comprise powdered activated carbon. Preferably the insert comprises the zeolite as a major component and activated carbon as a minor component based on a dry weight percentage. Optionally, a weight % ratio of the activated carbon to the zeolite or zeolite blend, as part of the insert, is in the range 0.01:1 to 0.05:1.

The powdered zeolite may comprise a particle size equal to or less than 0.15 mm and/or 0.045 mm and/or 0.075 mm. Optionally, the zeolite comprises a surface area of substantially 400 m²/g.

Preferably, 99% by weight of the zeolite may comprise a particle size equal to or less than 0.15 mm; 95% by weight of the zeolite may comprise a particle size equal to or less than 0.075 mm and 90% by weight of the zeolite may comprise a particle size equal to or less than 0.045 mm.

Preferably, the activated carbon comprises and is derived from coconut shell char. The activated carbon may comprise a surface area of substantially 1250 m²/g. Preferably, the polyacrylate superabsorbent comprises a granular configuration being at least one or a multiple order of magnitude greater in size than the particle size of the zeolite or activated carbon.

Synergistically, the zeolite and optionally the activated carbon may be bound to the superabsorbent granules by electrostatic forces. The superabsorbent may comprise sodium or calcium polyacrylate. Optionally, the zeolite and/or the activated carbon may comprise any metal impregnated activated charcoal.

Preferably, the superabsorbent and powdered zeolite or zeolite blend is housed within a water soluble paper sachet. The paper sachet may comprise sodium carboxy methyl cellulose and wood pulp. The edges of the sachet may be heat sealed so as to trap the granular superabsorbent and zeolite within the envelope formed by the soluble paper.

Alternatively, the zeolite or zeolite based blend may be encased within water soluble films (e.g. PVA films), gel caps, plastic straws/wands or formed as tablets. Moreover, the insert may comprise a plurality of separate units (e.g. tablets, gel caps, sachets). These units would then be inserted separately into the ostomy bag.

According to a second aspect of the present invention there is provided an ostomy bag comprising an insert as described herein. The insert may be permanently or temporarily attached to an internal wall of the ostomy bag using conventional means found in the art. For example, the insert may be attached to the internal walls via a flap, strap or permeable pouch or cover allowing release of the superabsorbent and odour absorbing material upon contact with the excreted body fluid.

Preferably, the insert comprises 1,000 mg to 10,000 mg of the polyacrylate superabsorbent and 25 mg to 5,000 mg of the zeolite or zeolite blend.

A specific implementation of the invention will now be described by way of example only, and with reference to the attached drawings in which:

FIG. 1 illustrates an ostomy bag comprising an insert configured to solidify liquid matter within the ostomy bag and control and reduce malodours according to a specific implementation of the present invention;

FIG. 2 illustrates a partial cut-away view of the ostomy bag insert of FIG. 1 formed as a sachet containing a granular and powdered material;

FIG. 3 illustrates a superabsorbent granule coated with a zeolite material;

FIG. 4 is a GC chromatogram of solution 1-3 μl/ml thioacetic acid and 0.5 μl/ml ethanethiol in water;

FIG. 5 is GC chromatogram of solution 2—aqueous solution containing superabsorbent polymer;

FIG. 6 is a GC chromatogram of solution 3—containing activated carbon;

FIG. 7 is a GC chromatogram of solution 4—containing activated carbon and superabsorbent polymer;

FIG. 8 is a GC chromatogram of solution 5—containing zeolite blend;

FIG. 9 is a GC chromatogram of solution 6—containing zeolite blend and super absorbent polymer;

FIG. 10 is a GC chromatogram of solution 7—containing hydrophobic zeolite;

FIG. 11 is a GC chromatogram of solution 8 containing hydrophobic zeolite and super absorbent polymer;

FIG. 12 is a GC chromatogram of solution 9 containing hydrophilic zeolite;

FIG. 13 is a GC chromatogram of solution 10 containing hydrophilic zeolite and superabsorbent polymer;

FIG. 14 is a GC chromatogram of solution 11 containing CW 90 Zn salt;

FIG. 15 is a GC chromatogram of solution 12 containing CW 90 Zn salt and superabsorbent polymer;

FIG. 16 is a graph of the percentage decrease of ethanethiol and thioacetic acid peaks for solutions 3 to 12;

FIG. 17 is a graph of the percentage decrease of ethanethiol peak with increasing absorbent compound concentration; and

FIG. 18 is a graph of the percentage decrease of thioacetic acid peak with increasing absorbent compound concentration.

The inventors provide a material blend configured to solidify excreted matter within an ostomy bag and to reduce odours within the ostomy bag which would otherwise be released from the bag when it is emptied by a patient. A material blend is housed within a water soluble sachet which provides a convenient means by which the liquid and odour absorbing material blend may be stored and transported prior to use within the ostomy bag. The dissolvable sachet may be used in all manner of pouches or bags designed for collecting body excretions such as ostomy, drainage bags or other applications where body fluids require thickening or gelling and odour control (neutralisation/absorption).

FIG. 1 illustrates an ostomy bag 100 comprising an internal chamber 105 and an inlet opening 101 surrounded by an annular adhesive pad 102. A drainage flap 103 is provided at a lower region 106 of bag 100. An odour controlling and liquid superabsorbent insert 104 is housed within internal chamber 105 and is dimensioned so as to pass through inlet opening 101 during initial insertion prior to attachment of bag 100 and through outlet opening 103 after empty and reuse of bag 100.

In use, ostomy bag 100 is secured to the skin of a patient at the abdominal region, via adhesive pad 102 such that inlet opening 101 is aligned with the stoma site formed in the patient. Accordingly, excreted matter passes through the stoma and into internal chamber 105 of ostomy bag 100 via inlet opening 101.

The excreted body fluid contacts insert 104 which acts to gel (partially solidify) the fluid matter and control malodours within internal chamber 105.

Following solidification of the excreted matter, the contents of the ostomy bag 100 may then be emptied via the flap arrangement 103 configured to dispense liquid and/or solid from internal chamber 105. Flap 103 may comprise any conventional tap or flap design configured to allow liquid and/or solid matter to be released from internal chamber 105. Following emptying of the bag, a new insert may then be inserted into internal chamber 105 via the flap 103 such that a user is not required to detach bag 100 from positioning around the stoma.

Referring to FIGS. 2 and 3, insert 104 is formed as a sachet comprising a water soluble paper having an upper layer 200 and a lower opposed layer 204. The edges of the upper and lower layers 200, 204 are heat sealed 201 to define an internal cavity 202 sealed along all four edges of the rectangular sachet. Insert 104 comprises liquid and odour absorbing material blend 203 (comprising a polyacrylate based superabsorbent 300 and a powdered zeolite 301) housed within internal cavity 202 formed by the upper and lower layers 200, 203. As will be appreciated by those skilled in the art, the present invention may comprise any specific polyacrylate comprising superabsorbent properties suitable for use to absorb fluids, excreted by the human body. The zeolite may comprise any natural or synthetic zeolite or zeolite composite or blend configured to control malodours of the type associated with human body excreted matter. It is preferred that the zeolite is a blend of a hydrophobic and a hydrophilic zeolite,

Referring to FIG. 3, it has been found advantageous for malodour control/reduction to coat the superabsorbent 300 with the zeolite 301. In particular, the superabsorbent, according to a specific implementation of the present invention, is formed as granules or pellets. In this configuration, the finely powdered zeolite readily coats the external surface of the granules or pellets providing an active blend exhibiting enhanced odour control over existing stoma bag inserts. The powdered zeolite may be maintained at the outer surface of the superabsorbent granules by, in part, the electrostatic interactions between the superabsorbent and the powdered zeolite.

According to one embodiment, the stoma bag insert 104 comprises a sodium polyacrylate superabsorbent 300. The water soluble sachet comprises sodium carboxy methyl cellulose and wood pulp comprising a thickness in a range 0.07 mm to 0.09 mm. The zeolite comprises a zeolite blend having a hydrophilic zeolite component and a hydrophobic zeolite component. The water soluble sachet comprises 2 g of sodium polyacrylate and 250 mg of zeolite.

According to a further specific embodiment, the insert 104 comprises sodium polyacrylate superabsorbent 300, the same water soluble sachet as described above, a zeolite blend having a hydrophilic and a hydrophobic component and powdered activated carbon.

Experimental Investigation

The effect of three odour absorbing compounds and a superabsorbent polymer on the volatilisation of ethanethiol and thioacetic acid from aqueous solutions have been investigated using GC headspace techniques.

It was found that all three of the odour absorbing compounds and the superabsorbent polymer are effective (to a greater or lesser degree) at reducing the volatilisation of ethanethiol and thioacetic acid from aqueous solutions at 37° C.

The most effective system for reducing the volatilisation of ethanethiol and thioacetic acid from aqueous solutions at 37° C. was found to be a hydrophilic/hydrophobic zeolite blend combined with the superabsorbent polymer. This system showed around a 95% reduction of the ethanethiol peak and 100% reduction of the thioacetic acid peak.

Results indicate that at 37° C. and at concentrations of above 60 mg/5 ml the zeolite blend combined with polymer has comparable effectiveness with carbon black and polymer at suppressing the volatilisation of ethanethiol and thioacetic acid from aqueous solutions.

Analysis

A GC headspace analysis method was developed during the course of the investigations and used to quantify the levels of the odorous thiol compounds, thioacetic acid and ethanethiol, in the headspace above aqueous samples, with and without the presence of each of the absorbing compounds. The work found that two compounds—a zeolite blend and CW90 Zn salt—gave results which were comparable to activated carbon. Both compounds have the advantage over carbon black of being opaque/white, which should enable easier examination of stoma bags containing the compounds.

The report below, details further investigations conducted into the absorption properties of the hydrophobic and hydrophilic zeolites and the CW90 Zn salt at temperatures more closely resembling body temperature and in the presence of a superabsorbent polymer.

Objectives

To test the capabilities of the zeolites and the CW90 Zn salt to absorb H₂S, thioacetic acid, ethanethiol and skatole both in pure aqueous solutions and in the presence of a superabsorbent polymer.

Method

A stock solution of the odorous compounds H₂S, thioacetic acid, ethanethiol and skatole were made up at with 2 mg/ml in water. The samples were analysed using a Perkin Elmer XL40 gas chromatograph with a Zebron ZB-624 capillary GC column (30 m×0.32 mm×1.8 u) with an FID detector.

No signals associated with H₂S and skatole were observed using the method. H₂S was not detected by the FID detector and skatole was insoluble in water and its low volatility meant that the concentration in the headspace at 40° C. was negligible.

As a result, a second stock solution was prepared with 3 μl/ml thioacetic acid and 0.5 μl/ml ethanethiol in water only. 5 ml of the stock solution was then added to each of the following compounds:

TABLE 1 Summary of the solutions prepared, detailing the odour absorbing compound employed, its quantity and the quantity of superabsorbent polymer. Mass of Odour absorbing Mass of superabsorbent Solution compound compound (mg) polymer (mg) 1 None 0 0 2 None 0 25 3 Activated Carbon 67 0 4 Activated Carbon 62 28 5 Zeolite Blend 62 0 6 Zeolite Blend 59 25 7 Zeolite Hydrophobic 60 0 8 Zeolite Hydrophobic 65 25 9 Zeolite Hydrophilic 60 0 10 Zeolite Hydrophilic 58 26 11 Cw90 Zn salt 60 0 12 Cw90 Zn salt 60 24

The GC analysis set up was as follows for all samples:

-   -   Injection port temperature: 140° C.;     -   Carrier gas (H₂) pressure 8 psi;     -   Oven program:         -   40° C. isocratic for 5 min;         -   Ramp to 90° C. at 10° C./min;         -   isocratic at 90° C. for 2 min;     -   FID detector temperature: 240° C.

Headspace sampling was carried out as follows:

-   -   Equilibrium time 7 minutes with shaking;     -   Pressurisation 0.5 minutes;     -   Injection 0.1 minutes;     -   Withdrawal 0.1 minutes;     -   Oven temperature 37° C.;     -   Needle 60° C.;     -   Transfer line 60° C.

Blank Results (Solutions 1+2)

Analysis of aqueous solution containing 3 μl/ml thioacetic acid and 0.5 μl/ml ethanethiol resulted in peaks at ˜2.5 minutes for ethanethiol and 5.75 minutes for thioacetic acid, the results are shown in FIG. 4

The same aqueous solution when added to 25 mg of superabsorbent polymer showed that the polymer itself had some odour absorbing qualities without the presence of any odour absorbing compounds, as shown in FIG. 5. The polymer was more effective at absorbing thioacetic acid than ethanethiol.

Summary of Results

Percentage decrease Percentage decrease of ethanethiol of thioacetic acid Solution Compounds peak (%) peak (%) 3 Carbon 74 90 4 Carbon + Polymer 91 100 5 Zeolite Blend 89 100 6 Zeolite Blend + 95 100 Polymer 7 Zeolite 32 100 Hydrophilic 8 Zeolite 32 100 Hydrophilic+ 9 Zeolite 80 50 Hydrophobic 10 Zeolite 96 100 Hydrophobic+ 11 Cw90 Zn salt 32 50 12 Cw90 Zn salt + 40 100 Polymer

Effect of Concentration

The effect of the concentration of the absorbing compounds and the polymer on the level of odours compound absorption were also investigated. 5 ml of the stock solution containing ethanethiol and thioacetic acid was added to vials containing masses of odour absorbing compounds ranging from ˜20 mg to ˜150 mg. The results are displayed in the tables below. Note: all experiments on the absorbing compounds were performed in aqueous solutions without polymer.

Activated Carbon:

Mass of compound Percentage decrease of Percentage decrease of (mg) ethanethiol peak thioacetic acid peak 27 87 100 39 87 100 63 93 100 103 100 100

Zeolite Blend:

Mass of compound Percentage decrease of Percentage decrease of (mg) ethanethiol peak thioacetic acid peak 22 53 100 40 80 100 59 91 100 101 98 100

Zeolite Hydrophobic:

Mass of compound Percentage decrease of Percentage decrease of (mg) ethanethiol peak thioacetic acid peak 19 53 50 43 77 75 60 83 75 102 95 95

Zeolite Hydrophilic:

Mass of compound Percentage decrease of Percentage decrease of (mg) ethanethiol peak thioacetic acid peak 19 7 100 40 20 100 60 20 100 100 20 100

Cw 90Zn Salt:

Mass of compound Percentage decrease of Percentage decrease of (mg) ethanethiol peak thioacetic acid peak 26 0 50 50 20 50 76 73 90 112 89 95

Superabsorbent Gel:

Mass of compound Percentage decrease of Percentage decrease of (mg) ethanethiol peak thioacetic acid peak 32 13 100 55 27 100 80 40 100 150 33 100

The performance of the absorbing compounds identified as solutions 3 to 12 are detailed in FIGS. 6 to 15 respectively.

A summary of the percentage decrease of the ethanethiol and thioacetic acid peaks for solutions 1 to 12, based on the gas chromatography results of FIGS. 4 to 15 are shown in FIG. 16. The effect of the percentage decrease of the ethanthiol peak with increasing absorbent compound concentration is illustrated in FIG. 17 and the percentage decrease of thioacetic acid peak with increasing absorbent compound concentration is shown in FIG. 18.

CONCLUSIONS

No signals associated with H₂S or skatole were observed using the GC headspace method. H₂S was not detected by the FID detector and skatole was insoluble in water and its low volatility meant that the concentration in the headspace at 40° C. was negligible.

All the odour absorbing compounds reduced the peak height of ethanethiol and thioacetic acid compared to the blank, solution 1. The polymer also reduced the peak heights of ethanethiol by 20% and thioacetic acid by 90%.

Almost all the odour absorbing compounds showed enhanced peak reduction of ethanethiol and thioacetic acid with the presence of the superabsorbent polymer, the hydrophilic zeolite was the only compound which showed little to no enhancement of ethanethiol absorption by addition of polymer.

The present results indicate that the hydrophobic zeolite is more effective at reducing the ethanethiol peak than the thioacetic acid peak, whilst the hydrophilic zeolite shows the opposite effect and is much less effective at reducing ethanethiol, but effective at reducing the thioacetic acid peak.

The Zeolite blend containing both hydrophilic and hydrophobic forms (solution 5) absorbed more ethanethiol and thioacetic acid than the individual zeolites themselves.

The Zeolite blend (solution 6) combined with the superabsorbent polymer appears to be the most effective system for reducing the volatilisation of ethanethiol and thioacetic acid from aqueous solutions at 37° C. The solution showed ˜95% reduction of the ethanethiol peak and 100% reduction of the thioacetic acid peak. The blend was successful because the hydrophobic zeolite had a greater effect on the absorption of ethanethiol and the hydrophilic zeolite a greater effect on the absorption of thioacetic acid.

At ˜37° C. the performances of the zeolite blend and activated carbon appear to be roughly comparable. Activated carbon is more effective at the lower concentrations (˜20 mg in 5 ml) at reducing the volatilisation of ethanethiol and thioacetic acid, but at higher concentrations (˜60-100 mg) the zeolite blend performs equally as well.

Cw 90 Zn salt was the least effective of the three compounds tested and showed only minor reductions on the levels of ethanethiol. Reductions in the thioacetic acid peak height were observed. At higher concentrations, in aqueous solutions, the Cw 90 Zn salt performs relatively well suppressing both the ethanethiol and thioacetic acid peaks. However, in the presence of the polymer it performed less well, possibly indicating an inhibiting effect of the polymer on the salt's performance.

Generally, increasing the concentration of the odour absorbing compound decreased the volatilisation of ethanethiol and thioacetic acid. The exception was the hydrophilic zeolite, which reached a plateau of ethanethiol reduction at ˜20%. 

1. An ostomy bag insert comprising: a polyacrylate superabsorbent; and a powdered zeolite; wherein the superabsorbent is coated with the powdered zeolite.
 2. The insert as claimed in claim 1 wherein the powdered zeolite comprises a particle size equal to or less than 0.15 mm.
 3. The insert as claimed in claim 1 wherein the zeolite comprises a particle size equal to or less than 0.075 mm.
 4. The insert as claimed in claim 1 wherein the zeolite comprises a particle size of equal to or less than 0.045 mm.
 5. The insert as claimed in claim 1 wherein the zeolite is a zeolite blend comprising a hydrophilic zeolite and a hydrophobic zeolite.
 6. The insert as claimed in claim 5 wherein the hydrophobic zeolite is an ammonium zeolite and the hydrophilic zeolite is a sodium aluminosilicate.
 7. The insert as claimed in claim 1 wherein the zeolite comprises a surface area of substantially 400 m²/g.
 8. The insert as claimed in claim 1 further comprising powdered activated carbon.
 9. The insert as claimed in claim 8 wherein a weight % ratio of the activated carbon to the zeolite as part of the insert is in the range 0.01:1 to 0.05:1.
 10. The insert as claimed in claim 1 wherein the polyacrylate superabsorbent is granular.
 11. The insert as claimed in claim 1 wherein the superabsorbent comprises sodium or calcium polyacrylate.
 12. The insert as claimed in claim 1 further comprising a water soluble paper formed as a sachet to house the superabsorbent and the zeolite.
 13. The insert as claimed claim 1 further comprising a water soluble film to house the superabsorbent and the zeolite.
 14. The insert as claimed in claim 1 further comprising a gel cap to house the superabsorbent and the zeolite.
 15. The insert as claimed of claim 1 further comprising a plastic straw or plastic wand to house the superabsorbent and the zeolite.
 16. The insert as claimed in claim 1 wherein the insert is formed as a soluble tablet.
 17. The insert as claimed in claim 1 comprising 1,000 mg to 10,000 mg of polyacrylate superabsorbent.
 18. The insert as claimed in claim 1 comprising 25 mg to 5,000 mg of the powdered zeolite.
 19. The insert as claimed in claim 1 comprising a metallic salt impregnated zeolite.
 20. An ostomy bag comprising an insert as claimed in claim
 1. 